Merge branch 'main' into remove-arg

.github/workflows/build.yml

@@ -231,10 +231,14 @@ jobs:
     name: >-
       Ubuntu
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
+      ${{ fromJSON(matrix.bolt) && '(bolt)' || '' }}
     needs: check_source
     if: needs.check_source.outputs.run_tests == 'true'
     strategy:
       matrix:
+        bolt:
+        - false
+        - true
         free-threading:
         - false
         - true
@@ -246,9 +250,16 @@ jobs:
         exclude:
         - os: ubuntu-24.04-aarch64
           is-fork: true
+        # Do not test BOLT with free-threading, to conserve resources
+        - bolt: true
+          free-threading: true
+        # BOLT currently crashes during instrumentation on aarch64
+        - os: ubuntu-24.04-aarch64
+          bolt: true
     uses: ./.github/workflows/reusable-ubuntu.yml
     with:
       config_hash: ${{ needs.check_source.outputs.config_hash }}
+      bolt-optimizations: ${{ matrix.bolt }}
       free-threading: ${{ matrix.free-threading }}
       os: ${{ matrix.os }}
 

.github/workflows/reusable-ubuntu.yml

@@ -6,6 +6,11 @@ on:
       config_hash:
         required: true
         type: string
+      bolt-optimizations:
+        description: Whether to enable BOLT optimizations
+        required: false
+        type: boolean
+        default: false
       free-threading:
         description: Whether to use free-threaded mode
         required: false
@@ -34,6 +39,12 @@ jobs:
       run: echo "::add-matcher::.github/problem-matchers/gcc.json"
     - name: Install dependencies
       run: sudo ./.github/workflows/posix-deps-apt.sh
+    - name: Install Clang and BOLT
+      if: ${{ fromJSON(inputs.bolt-optimizations) }}
+      run: |
+        sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh 19
+        sudo apt-get install bolt-19
+        echo PATH="$(llvm-config-19 --bindir):$PATH" >> $GITHUB_ENV
     - name: Configure OpenSSL env vars
       run: |
         echo "MULTISSL_DIR=${GITHUB_WORKSPACE}/multissl" >> "$GITHUB_ENV"
@@ -73,14 +84,18 @@ jobs:
         key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ inputs.config_hash }}
     - name: Configure CPython out-of-tree
       working-directory: ${{ env.CPYTHON_BUILDDIR }}
+      # `test_unpickle_module_race` writes to the source directory, which is
+      # read-only during builds — so we exclude it from profiling with BOLT.
       run: >-
+        PROFILE_TASK='-m test --pgo --ignore test_unpickle_module_race'
         ../cpython-ro-srcdir/configure
         --config-cache
         --with-pydebug
         --enable-slower-safety
         --enable-safety
         --with-openssl="$OPENSSL_DIR"
         ${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
+        ${{ fromJSON(inputs.bolt-optimizations) && '--enable-bolt' || '' }}
     - name: Build CPython out-of-tree
       if: ${{ inputs.free-threading }}
       working-directory: ${{ env.CPYTHON_BUILDDIR }}

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.8.2
+    rev: v0.9.1
     hooks:
       - id: ruff
         name: Run Ruff (lint) on Doc/
@@ -29,12 +29,10 @@ repos:
       - id: black
         name: Run Black on Tools/build/check_warnings.py
         files: ^Tools/build/check_warnings.py
-        language_version: python3.12
         args: [--line-length=79]
       - id: black
         name: Run Black on Tools/jit/
         files: ^Tools/jit/
-        language_version: python3.12
 
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v5.0.0
@@ -51,19 +49,19 @@ repos:
         types_or: [c, inc, python, rst]
 
   - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.30.0
+    rev: 0.31.0
     hooks:
       - id: check-dependabot
       - id: check-github-workflows
       - id: check-readthedocs
 
   - repo: https://github.com/rhysd/actionlint
-    rev: v1.7.4
+    rev: v1.7.6
     hooks:
       - id: actionlint
 
   - repo: https://github.com/woodruffw/zizmor-pre-commit
-    rev: v0.8.0
+    rev: v1.1.1
     hooks:
       - id: zizmor
 

Doc/faq/programming.rst

@@ -1906,28 +1906,30 @@ In the standard library code, you will see several common patterns for
 correctly using identity tests:
 
 1) As recommended by :pep:`8`, an identity test is the preferred way to check
-for ``None``.  This reads like plain English in code and avoids confusion with
-other objects that may have boolean values that evaluate to false.
+   for ``None``.  This reads like plain English in code and avoids confusion
+   with other objects that may have boolean values that evaluate to false.
 
 2) Detecting optional arguments can be tricky when ``None`` is a valid input
-value.  In those situations, you can create a singleton sentinel object
-guaranteed to be distinct from other objects.  For example, here is how
-to implement a method that behaves like :meth:`dict.pop`::
+   value.  In those situations, you can create a singleton sentinel object
+   guaranteed to be distinct from other objects.  For example, here is how
+   to implement a method that behaves like :meth:`dict.pop`:
 
-   _sentinel = object()
+   .. code-block:: python
 
-   def pop(self, key, default=_sentinel):
-       if key in self:
-           value = self[key]
-           del self[key]
-           return value
-       if default is _sentinel:
-           raise KeyError(key)
-       return default
+      _sentinel = object()
+
+      def pop(self, key, default=_sentinel):
+          if key in self:
+              value = self[key]
+              del self[key]
+              return value
+          if default is _sentinel:
+              raise KeyError(key)
+          return default
 
 3) Container implementations sometimes need to augment equality tests with
-identity tests.  This prevents the code from being confused by objects such as
-``float('NaN')`` that are not equal to themselves.
+   identity tests.  This prevents the code from being confused by objects
+   such as ``float('NaN')`` that are not equal to themselves.
 
 For example, here is the implementation of
 :meth:`!collections.abc.Sequence.__contains__`::

Doc/glossary.rst

@@ -115,7 +115,7 @@ Glossary
       :keyword:`yield` expression.
 
       Each :keyword:`yield` temporarily suspends processing, remembering the
-      location execution state (including local variables and pending
+      execution state (including local variables and pending
       try-statements).  When the *asynchronous generator iterator* effectively
       resumes with another awaitable returned by :meth:`~object.__anext__`, it
       picks up where it left off.  See :pep:`492` and :pep:`525`.
@@ -564,7 +564,7 @@ Glossary
       An object created by a :term:`generator` function.
 
       Each :keyword:`yield` temporarily suspends processing, remembering the
-      location execution state (including local variables and pending
+      execution state (including local variables and pending
       try-statements).  When the *generator iterator* resumes, it picks up where
       it left off (in contrast to functions which start fresh on every
       invocation).

Doc/library/email.contentmanager.rst

@@ -157,7 +157,13 @@ Currently the email package provides only one concrete content manager,
        :exc:`ValueError`.
 
        * For ``str`` objects, if *cte* is not set use heuristics to
-         determine the most compact encoding.
+         determine the most compact encoding.  Prior to encoding,
+         :meth:`str.splitlines` is used to normalize all line boundaries,
+         ensuring that each line of the payload is terminated by the
+         current policy's :data:`~email.policy.Policy.linesep` property
+         (even if the original string did not end with one).
+       * For ``bytes`` objects, *cte* is taken to be base64 if not set,
+         and the aforementioned newline translation is not performed.
        * For :class:`~email.message.EmailMessage`, per :rfc:`2046`, raise
          an error if a *cte* of ``quoted-printable`` or ``base64`` is
          requested for *subtype* ``rfc822``, and for any *cte* other than

Doc/library/importlib.rst

@@ -380,13 +380,15 @@ ABC hierarchy::
 
 .. class:: ResourceLoader
 
+   *Superseded by TraversableResources*
+
     An abstract base class for a :term:`loader` which implements the optional
     :pep:`302` protocol for loading arbitrary resources from the storage
     back-end.
 
     .. deprecated:: 3.7
        This ABC is deprecated in favour of supporting resource loading
-       through :class:`importlib.resources.abc.ResourceReader`.
+       through :class:`importlib.resources.abc.TraversableResources`.
 
     .. abstractmethod:: get_data(path)
 

Doc/library/os.rst

@@ -5411,6 +5411,8 @@ information, consult your Unix manpages.
 The following scheduling policies are exposed if they are supported by the
 operating system.
 
+.. _os-scheduling-policy:
+
 .. data:: SCHED_OTHER
 
    The default scheduling policy.
@@ -5514,7 +5516,7 @@ operating system.
 
 .. function:: sched_yield()
 
-   Voluntarily relinquish the CPU.
+   Voluntarily relinquish the CPU. See :manpage:`sched_yield(2)` for details.
 
 
 .. function:: sched_setaffinity(pid, mask, /)

Doc/library/sys.rst

@@ -8,7 +8,7 @@
 
 This module provides access to some variables used or maintained by the
 interpreter and to functions that interact strongly with the interpreter. It is
-always available.
+always available. Unless explicitly noted otherwise, all variables are read-only.
 
 
 .. data:: abiflags

Doc/library/time.rst

@@ -385,6 +385,8 @@ Functions
    The suspension time may be longer than requested by an arbitrary amount,
    because of the scheduling of other activity in the system.
 
+   .. rubric:: Windows implementation
+
    On Windows, if *secs* is zero, the thread relinquishes the remainder of its
    time slice to any other thread that is ready to run. If there are no other
    threads ready to run, the function returns immediately, and the thread
@@ -393,12 +395,19 @@ Functions
    <https://learn.microsoft.com/windows-hardware/drivers/kernel/high-resolution-timers>`_
    which provides resolution of 100 nanoseconds. If *secs* is zero, ``Sleep(0)`` is used.
 
-   Unix implementation:
+   .. rubric:: Unix implementation
 
    * Use ``clock_nanosleep()`` if available (resolution: 1 nanosecond);
    * Or use ``nanosleep()`` if available (resolution: 1 nanosecond);
    * Or use ``select()`` (resolution: 1 microsecond).
 
+   .. note::
+
+      To emulate a "no-op", use :keyword:`pass` instead of ``time.sleep(0)``.
+
+      To voluntarily relinquish the CPU, specify a real-time :ref:`scheduling
+      policy <os-scheduling-policy>` and use :func:`os.sched_yield` instead.
+
    .. audit-event:: time.sleep secs
 
    .. versionchanged:: 3.5